No comments? OK I'll post one. This is a fact-reporting article (observations, correlations) and at that it succeeds perfectly. It offers a tentative tying up of a number of loose ends. To me that's less convincing because we don't have all the ends yet so tying ends up now may mean making wrong connections. Lots of questions beckon, as always with Titan. If the dune material descends from the hydrocarbon haze this presumably happens at all latitudes, so what happens to it north and south of the tropical dune zone?

Atmospheric sintering is just one of the possible ways of making dune particles.(Remember, it's still not known exactly what is in the dune particles. RADAR dielectric constant suggests 'organic' (not ice).VIMS, which only sees the first few microns, suggests some aromatics with benzene-like stretches near 5 micron are present?) To really determine composition, some type of in-situ separation/then characterization would be needed. (LC-MS/MS Orbitrap). This will be a really neat problem for a future mission.

Even uglier, atmospheric chemistry on Titan isn't the same everywhere. Some recent CIRS data shows that the concentrations of different atmospheric materials vary widely by lattitude (multiple orders of magnitude). So the starting ingredients for the atmospheric chemistry is different in different locations. That could also have an effect on what gets constructed in the atmosphere and then deposited on the surface.

So you'd want to send that LC-MS/MS Orbitrap down to different places. Titan's surface will taste different depending on your location. That might be one possible explanation for polar zones being different than equatorial zones.

... Lots of questions beckon, as always with Titan. If the dune material descends from the hydrocarbon haze this presumably happens at all latitudes, so what happens to it north and south of the tropical dune zone ...

and of course in the Xanadu region which lies WITHIN the tropical zone at a LOWER elevation than the surrounding dune seas and presumably is OLDER geologically than the dune fields!

IMAGE COPYRIGHT
Images posted on UnmannedSpaceflight.com may be copyrighted.
Do not reproduce without permission. Read
here for further information on space images and copyright.

OPINIONS AND MODERATION
Opinions expressed on UnmannedSpaceflight.com are those of the
individual posters and do not necessarily reflect the opinions
of UnmannedSpaceflight.com or The Planetary Society. The all-volunteer
UnmannedSpaceflight.com moderation team is wholly independent
of The Planetary Society. The Planetary Society has no influence
over decisions made by the UnmannedSpaceflight.com moderators.

SUPPORT THE FORUM
Unmannedspaceflight.com is a project of the Planetary Society
and is funded by donations from visitors and members. Help keep
this forum up and running by contributing
here.